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The King of Sausage!!
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I am shooting a remington r-15 in 223 cal. My question is it has an 18 inch barrel with a 1 in 9 twist. I am told I lose roughly 50 per sec per inch on a shorter barrel. Ballistics and velocity are usually base on a longer barrel with x amount of pressure. Does this pressure drop in a shorter barrel along with velocity? Will I be loading a hot load if I try and increase my velocity? Or is the pressure in relation to the shorter barrel less?
 

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Very good question and being new to reloading myself, and also shooting the Remington R-15... I would be VERY interested to hear others replies.

Let me know what you find out!
 

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I load and shoot two ars one with a 1/8 twist and other a1/9 twist. The 1/8 is a 20 in. barrel and it shoots up to and including 80 gr. Matchking bullets. The 1/9 twist will shoot the 62 gr. and 55 gr. quite well, it is a 16 in. barrel. Follow the manuals and watch the brass and powder charge, mil. spc. brass is thicken in the shell so it does not have the case volume of the regular 223. The velocity loss difference is some times figured at 50 ft/sec/in. Don't worry about that if you do your job the bullet will do its job. The important thing to do is to shoot over a cronagraph and actuall see what the velocity actually is and use the ballistic tables for that bullet. Hornday manual is quite good, they have ballistics on there web site. The manual is quite good with its contents. The biggest thing is your gas port close to the upper receiver or is it longer, the short ones are around 6in. and the longer ones are 12 in. Watch for primer being flattened to much and holes in the primer caused by excessive pressure. The book tell all about that stuff. I have a long range bolt gun that has a 28 in. barrel and an old Swedish Mauser that has a 29.5 in. barrel Long barrels have there place. I have a couple of rifles with 16 in. barrels and I don't plan on changing any of them one way or another. back to the original question don't change the powder charge to make up the difference it may not work on another rifle if you end up with another 223. I hope this helps, I get to rambling sometimes.
 

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dont mess with the powder charge find what works in your rifle for you and use it.
ars can be very accurate. with iron sites 300 yard is no problem with a well zeroed weapon. would love to see what could do with a scope on it.
 

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Barrel length won't affect pressure that much. Just don't go over max powder charges according to your reloading source. You may loose some velocity but most generic velocities for 223 are with a 22" barrel. The only way to really tell is to get a chronograph. I've been reloading for 10 years and just because the manual give you a velocity doesn't mean it is accurate. For instance 38 gr of H 380 is supposed to give you 3800 fps with a 50 gr bullet in a 22-250 with a 26" barrel. Its more like 3550-3650. You just have to play with alot of powders and bullet weights and see what works for your gun other R-15 exactly like yours will still like different loads.
 

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Does this pressure drop in a shorter barrel along with velocity?
No. I'll try and hack thru this for you.

Lets say you have a 18" and a 24" long barreled rifle. Using the same ammo your chamber pressures are the same at the moment of powder ignition (given of course they have identical chamber diamentions etc) The pressure remains the same in each rifle all the way down the bore (think of it like a race) until the bullet leaves the shorter barrel of the two. The pressure drops all the way off when the bullet exits the bore giving you a velocity of X in a 18" barrel. In the longer barrel the bullet is still being pushed by the pressure so its velocity is still increasing until it exits the bore, giving you a higher velocity. The longer the bullet is in the bore being push by gas pressure, the faster it will go. Thats about as good as I can put it.

I wouldnt get to worked up over lost velocity. Its totally conceivable that your 18in. barreled rifle could shoot as fast as a 20" with a given load, some barrels are faster than others, no two are alike they say. I used to have a friend that was eatin up with the velocity bug. I always used to ask him if he thought that elk could tell the difference between 3100 FPS and 3200FPS.... Do you think it hurt them a 100 fps more?
 

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The velocity thing is right on, I go to the point of using the same bullet as much as possible due to how they react. That is not to say that I am after bench rest type groups it is that I have taken it to kind of extreme. My biggest thing is a thick barrel will more often that not shoot smaller groups that a light weight one. Some of my hunting is done is some rugged areas and I will take a short barrel is those times. That is the reason varmint barrels as always so thick. There is always exceptions to every rule.
 

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Be vewy, vewy quiet!
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I agree with furhunter. I have reloaded for over 30 years. I used to be preoccupied with velocity. Now, I load for ballistics. Lots of times a 5 grain heavier bullet going 200 to 300 fps slower will give you better downrange trajectory and retained energy than a lighter, faster bullet. As stated, check loads through YOUR rifle through a chrony, take that data and use one of the online ballistics calculator and tailor a load for the shot distances you are likely to encounter. I guarantee you the time it takes for a bullet to travel 200 yds @ 2800 fps vs. 3200 fps in a fraction of a second and your target will never know the difference.
 

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knapper said:
The velocity thing is right on, I go to the point of using the same bullet as much as possible due to how they react. That is not to say that I am after bench rest type groups it is that I have taken it to kind of extreme. My biggest thing is a thick barrel will more often that not shoot smaller groups that a light weight one. Some of my hunting is done is some rugged areas and I will take a short barrel is those times. That is the reason varmint barrels as always so thick. There is always exceptions to every rule.
I feel I have to pass on a little something here that isnt thought about much.

Yes a heavy barrel is more rigid than a pencil thin tube, its important to remember any barrel will shoot a good group if its a good barrel. A pencil thin barrel wont make a colony varmint shooter but it will serve you well in any hunting condition. We dont shoot groups at coyotes, we dont shoot them at elk, deer, or anything else. The first cold bore shot is the most important. It doesnt matter if its from a buggy whip thats screwed on to your action.
 

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Does this pressure drop in a shorter barrel along with velocity?

Yes. If the powder is too slow, it will not reach a peak before projectile exits the barrel.

Will I be loading a hot load if I try and increase my velocity?

No. Shorter barrels require fast burning powders. You can shoot whatever velocity you'd like to, as long as you use the correct powder....and stay within manual limits for that powder.
Also, you must consider that your AR platform works on gas pressure to cycle the bolt.... Too much pressure too quickly and your bolt will be slamming back with unnecessary force that could possibly damage all kinds of things!

My 18" barreled Armalite loves 75gr AMAX with Varget and CCI BR primers in re-worked LC brass

Scott (handloadersbench.com is helpful) B
 

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Yes! shorter barrels require faster-burning powders. One would like all the powder to burn within 95 percent of barrel length, because powder burning after the bullet leaves the muzzle creates FLASH but no additional velocity. RamShot X-Terminator and Alliant RL-10x perform this skill admirably, whilst Varget seems T-O-O S-L-O-W to completely combust within SHORT barrels. Powder burn-rates are available throughout many manuals and Internet sites. Varget is a great powder under correct circumstances! Primer choice has a slight effect on burning speed, but not as much as ambient temperature! Sixty degrees is not ninety degrees and no powder available will compensate for this difference! Cliffy
 

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Just something to add. I have been using Ramshot TAC and X-Terminator powders for a while now. I couldn't get good deviation numbers with Varget so I change due to a suggestion from a friend. The TAC is good for 55 grn to 88 grn bullets and X-Terminator works well for the light ones on up to 68 grns. The last time I chronoed my deviation was a miracle 5 feet over 5 shots. That was also shot over 2 chrono's at a USPSA 3 gun match. This is key to making long range shots IMHO, constistant velocity everytime. Not bad out of a Dillon 650 progressive loader. The Ramshot powders meter like a champ too.

Here's a 55 grn load for you: 26.5 grns of TAC, OAL of 2.255. Get's me right at 2990 fps out of a 18 inch barrel. Link is posted below:

http://www.ramshot.com/powders/

Chris C.
 

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headhunter25, I like Ramshot powder also. I am useing it in three calibers 30-06,6.5X55, and 22-250. Have not cronoed aany of them yet , but they are giving serious accuracery.
 

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I get good accuracy myself. I think once you get your load tuned to your rifle, the constistancy of the powder really shines. I like the fact that in .223 it's not a compressed load like the Varget was. I'm going to start loading some 6.5 Grendel with the TAC soon. Kinda curious to see how the accuracy is in that caliber.

Chris C.
 

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Furhunter when it comes to hunting I feel that it is best to know my bullets path to the distance I expect to encounter. After I find the best grouping loads for my firearm of choice where it is a rifle or a hand gun I shoot from standing and make sure what I an shooting will then be on out to the planned distance I will shoot. I fire as much in this type of drills and include self induced stress so when it comes time to make the shot that counts I have confidince in my ability to make the shot as best as can be done. Shooting standing as well as reloading drills with rifle and hand guns to improve makes for better in the field shooting. I work up one load and use it for every thing with that firearm. For winter trips I go as far as putting the all of the firearms in cases that I will be using and let them cool down to outside tempature, that is after I make sure they are properly lubed or in some cases delubed they will work at temps. to -30to -40 degrees. Once it warms up I relubed and are ready to go for the warmer weather. Yes I shoot a lot of paper but each shot is aimed at either paper or animal, the paper ones are a lot harder to skin out and tough to eat.
 

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The key to good accuracy in any handload is CONSISTANCY in your loads. I'm getting some mixed vibes reading some of the posts to your question. Your max pressure is reached 2-3" into the barrel so a shorter barrel will have absolutely no affect on MAX pressures, you will loose some velocity with a shorter barrel but your pressures will not change. The farther your bullet travels down the barrel the more space there is behind the bullet in the barel to allow pressures to drop. DO NOT load hotter than recomended loads they don't purposly list them low for safety as many people beleive. Please remember that internet advice should only be taken for what it is...advice. You have no clue as to the experience of the giver and should be cautious. Here is a tip for you, start with the lowest listed load for your bullet/powder combo, load 4 rounds, add .5gr load another 4, etc...etc untill you hit max load. most powders give you a window of 3-4 grains. Hit the bench and shoot (2) 2 shot groups at the same target allowing a cool down period between 2 shot groups and clean your barrel before running the next charge weight. You will probably be suprised to find your peak accuracy will be less than max loads. Keep checking for flattened primers. Reloading is not a place for individulism or bravery.
 
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